2-7 players. players try and plant beans and harvest them for money. the crux of this game is the trading - and similar to "settlers of catan", it's often important to stall during your turn to make sure you're getting the best deal. a lot of times it seems like people get bored with it about half-way through, but it's still a popular choice.
2. Six Nimmt
2-10 players. players choose cards at their own hand which are simultaneously played on the board. if you play a card which ends up filling the 6th slot on the board, you get that row of cards, so it's important to predict correctly which rows your opponents will play in. despite the minimal amount of player interaction, i find this to be more of a social game than most.
3. Ricochet Robots
2-20 players. players observe a board of robots and try and figure out how to get the selected robot to its goal in the fewest moves. kind of like "set" for the spatially inclined. the "catchup rule" which is included in ricochet-robots prevents beginners from being totally alienated. it is a good game to pick if you want your friends to quiet down.